It is well known in the field of automatic harmonization to generate a group of one or more harmony notes to accompany the melody note selected by a performer. Prior art methods have utilized both mechanical and electronic means to occasion the sounding of one or more notes below the melody note. In general, these systems add only the harmony notes selected on the accompaniment keyboard. These notes are sounded in a limited, preselected musical compass below the selected melody note. Examples of such systems are found in U.S. Pat. Nos. 3,283,056 issued Nov. 1, 1966 for "CONTROLLED HARMONIZATION FOR MUSICAL INSTRUMENTS", a mechanical system, and 3,929,051 issued Dec. 30, 1975 for "MULTIPLEX HARMONY GENERATOR", an electronic system.
Systems as above-referenced only approximate musically optimal harmony. Oftentimes, harmony, of which the above is an approximation, is best achieved by adding tones from the scale of the selected harmony chord other than chordal tones.
In popular music, melody notes which are not chord tones of the given harmony may be classified as various kinds of passing tones (i.e., appoggiaturas, suspensions, etc.), according to their position and function relative to the scale from which the given harmony was derived. By harmonizing such tones accordingly, the skilled musician may prevent harmony tones from making awkward skips, provide more logical voice leadings and increase harmonic interest. It is additionally customary for the skilled musician to add additional harmonizing tones such as sixths, sevenths, and ninths not present in the given chord to melody notes while sometimes omitting certain of the tones of the given harmony. These techniques add "fullness" and "color" to the sound.
For example, in FIG. 7 there is shown a line of music from the tune "Melancholy Baby". The topmost set of bars contains the melody of the piece while the bottommost contains its harmony. Using the standard orchestration control systems described above, one would sound the embellished melody of the second line of music (written in treble clef). ("Embellished" as referred to in this application is to be understood to be of the homophonic type wherein homophonic denotes music in which a single melody is supported by chords as distinguished from monophonic and polyphonic.) A preferred musical harmonization (which, it will be seen, is obtained by means of the present invention) is contained in the third set of lines.
Comparing the second and third lines of FIG. 7, starting with the first note ("E"), line three presents a four-part harmonization by adding the tones "C", "A" and "G" to the melody tone "E". The note "A", for example, is not part of the given harmony. The second melody note ("F") presents a more complex situation. Line two shows the addition of "C" and "G" (the same two notes added to melody note "E"). Since melody note "F" is not compatible with the harmony tone "E" of the given harmony, the "E" note is omitted, leaving a poorly defined chord (a "C" major chord containing the suspended note "F"). The melody note "F" comprises a passing tone. Proper harmonization is shown in line three, the tones "D", "C" and "A" forming a passing chord. Line two shows the third melody note, "F.music-sharp.", harmonized with the same two tones as before, "C" and "G". When combined, these three tones make an unpleasant sound comprising no chord at all but rather a tone cluster which has no harmonic function. The proper harmonization shown in line three includes the tones "D.music-sharp.", "C" and "A" with the appoggiatura "F.music-sharp." as a passing chord. The fourth melody note, "G", is also present in the given harmony. In line two, only the tones "E" and "C" are added. The proper harmonization indicated in line three adds the tones "E", "C" and "A". Line two shows the tones "G" and "E" added to the fifth melody note, "D". The chosen configuration presents a cadencial feeling of repose which incorrectly sounds as if the song could end at this point. Line three shows the harmonization of the appoggiatura note "D" with the tones "B", "G" and "E" which avoids the cadencial feeling yet comprises a substitute harmony for the given harmony ("C" major). The sixth ("C") and seventh ("G") melody notes are harmonized in the same fashion as the first and fourth while the eighth ("G" flat or "F" sharp) is harmonized in the same fashion as the third melody note. Regarding the ninth melody note ("F"), a comparison of the second and third lines shows the omission of the "E", present in the given harmony, since it is incompatible with the melody note "F". Line two adds the tones "C.music-sharp.", "A" and "G" whereas line three substitutes the tone "B" for the tone "A" and also adds the tones "C.music-sharp." and "G" to provide a richer sound. In accompanying the tenth melody note ("E"), line three includes the tone "A" instead of "B".
Present-day automatic harmonization systems are thus limited musically by their inability to utilize advantageous non-chordal or non-scale tones when these notes are not explicitly sounded by the musician. This inability becomes particularly critical when a musician of limited ability and/or dexterity seeks to sustain an accompanying chord with only a minimum number of tones. In such instances, chordal tones selected to accompany the melody will occasionally provide only a simple and plain sound, not always musically correct, including potential tonal skips or dissonant combinations, when played on present-day orchestration control systems. Thus, while the aforementioned systems have advanced the art by expanding the playing range of many musicians, they still do not incorporate some significant aspects of musicianship and do not derive the accompaniment notes on the basis of harmonic relationship between the melody and the selected chord.
Melody notes not contained within the tones of the chord defined by the accompaniment are referred to as "passing tones". As is the case in the above example, most melodies contain some notes which are not tones of the selected chord. The passing tones may be either non-chordal or non-scale with respect to the harmony defined by the accompanying chord. These passing tones are, however, intimately tied both to the melody and to the harmony; the existence and definition of such a harmonic relationship is necessary for selecting appropriate accompaniment notes to augment the melody.
The table below, presenting a set of tonal relationships, illustrates these musical principles. It lists appropriate accompaniment notes for a major chord having a root of C. Each of the twelve columns of the table corresponds to an indicated melody note. Thus, if the melody note selected is F, a musically proper set of accompaniment notes for a major chord having root C is D, C, A, and F, selected from column 6 of the table.
TABLE 1 ______________________________________ C Major With Added Notes 1 2 3 4 5 6 7 8 9 10 11 12 ______________________________________ C C.music-sharp. D D.music-sharp. E F F.music-sharp. G G.music-sharp. A A.music-sharp. B (1) A A.music-sharp. B C C D D.music-sharp. E 6E G G G (2) G G G A A C C C C E E E (3) E E E F.music-sharp. G A A A A.music-shar p. C D C (4) C C.music-sharp. D D.music-sharp. E F F.m usic-sharp. G G.music-sharp. A A.music-sharp. B ______________________________________
Accordingly, a skilled musician appreciates that a different chord type, such as minor or seventh, will result in different accompaniment note combinations, as reflected in each of the melody note columns. In addition, he knows that each of the five chord types will vary according to the style of voicing desired, resulting in a different proper set of accompaniment notes, for each melody note and chord type. For this reason, there exists a separate set of five tables (one table for each of the chord types--major, minor, seventh, augmented and diminished) containing appropriate accompaniment notes for each of the common styles of voicing: open (three-note or four-note), closed (three-note or four-note), block, duet (country or common) and hymnal.
The desirability of selecting a group of accompaniment notes from a table as above, the table being derived on the basis of the harmonic relationship between the melody and the selected chord, is evident from the preceding musical discussion. However, disregarding for the moment the complications added when one desires a variety of voicing styles, the use of such a method occasions a difficult-to-manage information storage and retrieval problem. Since there are five possible chord types and twelve possible roots for each of twelve melody notes, 720 (5.times.12.times.12) memory locations are required to store each set of four accompaniment notes (certain voicing styles may require more or less than four accompaniment notes for optimal harmony) for each style of voicing.
In accordance with the present invention, a method and apparatus are provided for enhancing the musical quality of a piece as played by a performer on an electronic musical instrument by introducing harmonious accompaniment notes selected without being limited to tones of a "recognized" chord, and without being limited to a predetermined compass beneath a "recognized" melody note, using minimal hardware and storage capability for practical implementation; the apparatus incorporates significant additional musical features including voicing style selectivity and a selective orchestration capability.
More particularly, there is provided in one of its aspects a method for embellishing a melody represented by the actuation during a time frame of one or more playing keys of a musical instrument keyboard capable of representing a plurality of notes. The invention defines a method including the selection and recognition of at least one chord. At least one accompaniment note is then derived from the harmonic relationship of said melody to said chord. The melody and accompaniment notes are then sounded to produce an embellished melody.
In a further aspect, the present invention comprises a method for deriving a signal representative of at least one accompaniment note chosen according to melody and harmony. In this aspect, melody and harmony signals are generated that are responsive to the actuation of the keys of a keyboard. A plurality of listings of harmonious accompaniment notes, stored according to musical chord type, is addressed to locate at least one accompaniment note in accordance with the chord root and the melody note. An accompaniment note signal is then generated responsive to the located accompaniment notes.
In a third aspect, apparatus is provided for sounding at least one accompaniment note. The apparatus includes means for generating signals responsive to both melody and harmony. Additionally, there is provided means for storing at least one accompaniment note and for locating the accompaniment note and generating a signal responsive thereto. Finally, means are provided, responsive thereto, for sounding the selected accompaniment note.
These and other objects, advantages and features of the present invention will appear for purposes of illustration, but not of limitation, in connection with accompanying drawings wherein like numbers refer to like parts throughout and wherein: